Abstract: ZrCN single layer and Zr/ZrCN multilayered hard coatings, deposited by reactive magnetron sputtering, were investigated as possible candidates to be used as protective layers on medical implants. The elemental composition, hardness and adhesion of the coatings were analyzed. "In vivo" investigations on rats were carried out in order to examine the biomedical effects of coated implants. After 8 weeks of periosseous implantation, the blood parameters and the reaction of the surrounding tissues to the implants were evaluated. For comparison, uncoated stainless steel 316L implants were also investigated.